trifloxystrobin and tebuconazole

Trifloxystrobin-tebuconazole (TFS-TBZ) is a novel, broad-spectrum fungicide that has been frequently detected in both the environment and agricultural products. However, its adverse effects on aquatic organisms remain unknown. In this study, the adverse effects of ecologically relevant TFS-TBZ concentrations (i.e., 75.0, 112.5, and 150.0 μg/L) on the heart and development of zebrafish were investigated. TFS-TBZ was found to substantially hinder development, inhibit growth, and cause significant abnormity at higher concentrations. Moreover, TFS-TBZ caused severe pericardial edema, heart loop failure, cardiac linearization, and ultra-slow heartbeat, implying that TFS-TBZ might induce congenital heart disease. TFS-TBZ inhibited Notch signaling and increased the intracellular generation of reactive oxygen species, resulting in decreased myocardial cell proliferation and increased apoptosis. The use of sodium valproate and Gadofullerene illustrated the relevance of the Notch signaling system and oxidative stress. Finally, TFS-TBZ exposure conveys severe developmental toxicity to the zebrafish heart. The underlying mechanism is regulation notch mediated-oxidative stress generation, implying that TFS-TBZ may be potentially hazardous to aquatic organisms in the environment.

Topics: Acetates; Animals; Embryo, Nonmammalian; Imines; Oxidative Stress; Strobilurins; Triazoles; Zebrafish

Black rot, caused by Ceratocystis fimbriata, is one of the most destructive disease of sweet potato worldwide, resulting in significant yield losses. However, a proper management system can increase resistance to this disease. Therefore, this study investigated the potential of using tebuconazole (TEB) and trifloxystrobin (TRI) to improve the antioxidant defense systems in sweet potato as well as the inhibitory effects on the growth of and antioxidant activity in C. fimbriata. Four days after inoculating cut surfaces of sweet potato disks with C. fimbriata, disease development was reduced by different concentrations of TEB + TRI. Infection by C. fimbriata increased the levels of hydrogen peroxide (H

Topics: Acetates; Antioxidants; Ceratocystis; Disease Resistance; Drug Synergism; Hydrogen Peroxide; Imines; Ipomoea batatas; Lipoxygenase; Malondialdehyde; Microbial Viability; Reactive Oxygen Species; Strobilurins; Triazoles

Topics: Acetates; Adolescent; Adult; Aged; Child; Child, Preschool; Female; Fungicides, Industrial; Humans; Imines; Limit of Detection; Linear Models; Male; Middle Aged; Oryza; Pesticide Residues; Reproducibility of Results; Risk Assessment; Soil; Strobilurins; Triazoles; Young Adult

Topics: Acetates; Adult; Child; Dietary Exposure; Fruit; Fungicides, Industrial; Gas Chromatography-Mass Spectrometry; Half-Life; Humans; Imines; No-Observed-Adverse-Effect Level; Pesticide Residues; Risk Assessment; Solanum lycopersicum; Strobilurins; Triazoles

The present study was done to assess the dissipation behavior, decontamination, and half-life time of ready-mix formulation of trifloxystrobin (25% w/w) and tebuconazole (50% w/w) in okra and soil under the crop after foliar spray at fruiting stage. Samples of okra and soil were collected periodically, i.e., zero (2 h after spray), 1, 3, 5, 7, 10, 15, 20, and 25 days after third application at a 7-day interval. Residues of these fungicides were determined by gas liquid chromatography (GLC) equipped with electron capture detector (ECD) and gas chromatography-tandem mass spectrometry (GCMS-triple quadruple). The limits of quantification (LOQ) and detection (LOD) for both the fungicides were 0.01 and 0.003 mg kg

Topics: Abelmoschus; Acetates; Decontamination; Environmental Monitoring; Fruit; Fungicides, Industrial; Half-Life; Imines; Pesticide Residues; Soil; Strobilurins; Triazoles

Late wilt, a disease severely affecting maize fields throughout Israel, is characterized by relatively rapid wilting of maize plants before tasseling and until shortly before maturity. The disease's causal agent is the fungus Harpophora maydis, a soil-borne and seed-borne pathogen, which is currently controlled using reduced sensitivity maize cultivars. In a former study, we showed that Azoxystrobin (AS) injected into a drip irrigation line assigned for each row can suppress H. maydis in the field and that AS seed coating can provide an additional layer of protection. In the present study, we examine a more cost-effective protective treatment using this fungicide with Difenoconazole mixture (AS+DC), or Fluazinam, or Fluopyram and Trifloxystrobin mixture, or Prothioconazole and Tebuconazole mixture in combined treatment of seed coating and a drip irrigation line for two coupling rows. A recently developed Real-Time PCR method revealed that protecting the plants using AS+DC seed coating alone managed to delay pathogen DNA spread in the maize tissues, in the early stages of the growth season (up to the age of 50 days from sowing), but was less effective in protecting the crops later. AS+DC seed coating combined with drip irrigation using AS+DC was the most successful treatment, and in the double-row cultivation, it reduced fungal DNA in the host tissues to near zero levels. This treatment minimized the development of wilt symptoms by 41% and recovered cob yield by a factor of 1.6 (to the level common in healthy fields). Moreover, the yield classified as A class (cob weight of more than 250 g) increased from 58% to 75% in this treatment. This successful treatment against H. maydis in Israel can now be applied in vast areas to protect sensitive maize cultivars against maize late wilt disease.

Topics: Acetates; Antifungal Agents; Ascomycota; Benzamides; Dioxolanes; Imines; Plant Diseases; Pyridines; Strobilurins; Triazoles; Zea mays

Dissipation kinetics of tebuconazole, trifloxystrobin and its acid metabolite residues were studied in tea under tropical field conditions using GC-MS (SIM). The average recoveries ranged from 80.7% to 105.8%, with a RSD of <9.3%. Dissipation rate for both doses applied followed first-order kinetics, with half-lives in green leaves in the range of 2.8-3.3 and 2.9-3.3 days; ranges in processed tea were 2.7-3.6 days for trifloxystrobin and 3.0-3.1 days for tebuconazole. The trifloxystrobin residues were not transferred into the tea infusion during the infusion process; tebuconazole did transfer, in the range of 14.3-18.9%. As the theoretical maximum residue contributions on tea from initial deposits were found to be less than the maximum permissible intake values, at the recommended application dose a withdrawal period of 23 days before consumption should be applied to reduce risk.

Topics: Acetates; Food Safety; Imines; Kinetics; Strobilurins; Tea; Triazoles

A rapid, simple, and selective analytical method for the simultaneous determination of tebuconazole, trifloxystrobin, and its metabolite trifloxystrobin acid residues in gherkin and soil was developed and validated by gas chromatography coupled with mass spectrometry. The samples were extracted with acetonitrile and cleaned up by dispersive solid-phase extraction with primary secondary amine sorbent. The limit of quantification of the method was 0.05 mg/kg for all three compounds. The method was validated using blank samples spiked at three levels and recoveries ranged from 83.5 to 103.8% with a relative standard deviation of 1.2 to 4.8%. The developed method was validated and applied for the analysis of a degradation study sample. The residues of trifloxystrobin and tebuconazole were found to dissipate following first-order kinetics with half-life ranging between 3.31-3.38 and 3.0-3.04 days, respectively, for two different dosages. Pesticide residues were below the European Union maximum residue level after seven days for trifloxystrobin (0.2 mg/kg) and ten days for tebuconazole (0.05 mg/kg), which suggested the use of this fungicide mixture to be safe to humans. These results can be utilized in formulating the spray schedule and safety evaluation on trifloxystrobin and tebuconazole in gherkin crop.

Topics: Acetates; Chemical Fractionation; Cucumis sativus; Fungicides, Industrial; Gas Chromatography-Mass Spectrometry; Imines; Methacrylates; Pesticide Residues; Soil Pollutants; Strobilurins; Triazoles; Vegetables

An evaluation of residue levels of trifloxystrobin and tebuconazole was carried out on mango fruits after treatments with the combined formulation, trifloxystrobin (25 % w/w) and tebuconazole (50 % w/w), at standard and double doses of 250 + 500 and 500 + 1000 g a.i. ha(-1), respectively. Extraction and purification of the mango fruit samples were carried out by the QuEChERS method after validating the analytical parameters. Determination of the fungicides was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The limits of detection (LOD) and limits of quantification (LOQ) for both fungicides were 0.015 μg mL(-1) and 0.05 mg kg(-1), respectively. The residue levels of trifloxystrobin for standard and double-dose treatments were 0.492 and 0.901 mg kg(-1) and for tebuconazole were 0.535 and 1.124 mg kg(-1), respectively. A faster dissipation of tebuconazole in mango fruit was observed compared with that for tebuconazole. Dissipation of trifloxystrobin and tebuconazole in mango followed first-order kinetics, and the half-lives were 9 and 6 days, respectively. The preharvest intervals (PHI), the time taken for the combined residues of trifloxystrobin and tebuconazole to dissipate to their permissible levels (maximum residue limits), were 14 and 20 days for standard and double doses, respectively. At harvest, mature mango fruit and soil were free from fungicide residues.

Topics: Acetates; Chromatography, Gas; Environmental Monitoring; Fruit; Fungicides, Industrial; Gas Chromatography-Mass Spectrometry; Half-Life; Imines; Kinetics; Mangifera; Methacrylates; Pesticide Residues; Soil; Soil Pollutants; Strobilurins; Triazoles

Supervised field trials at two locations in 2012 and 2013 were conducted to evaluate the dissipation, terminal residues, and safety evaluation of Nativo 75 water dispersible granule (WG) (25 % trifloxystrobin + 50 % tebuconazole) on ginseng and soil following foliar application at a recommended dose 150 (50 + 100) and 1.5 times of the recommended dosage 225 (75 + 150) g a.i. ha(-1). The average recoveries of trifloxystrobin and tebuconazole at three spiking levels in ginseng root, stem, and leaf and in soil were in the ranges of 81.0-96.8 % and 80.2-97.5 % with relative standard deviations (RSDs) of 4.92-13.13 % and 4.67-8.35 %, respectively. The half-lives of trifloxystrobin and tebuconazole were 5.92-9.76 days and 4.59-7.53 days, respectively. The terminal residues were all below the maximum residue limits (MRLs) of EU, USA, Canada, Japan, and South Korea. The food safety was evaluated by comparing the estimated daily intake (IEDI) with its acceptable daily intake (ADI). IEDI values calculated from residue data were found to be far less than the ADI on ginseng. Therefore, it would be unlikely to cause health problems induced by Nativo 75 WG use on ginseng at a dosage of 150-225 g a.i. ha(-1).

Topics: Acetates; Environmental Monitoring; Fungicides, Industrial; Half-Life; Imines; Methacrylates; Panax; Pesticide Residues; Plant Leaves; Plant Stems; Soil; Soil Pollutants; Strobilurins; Triazoles

Residue study of trifloxystrobin and tebuconazole on gherkin was carried out at two locations (Bangalore and Gouribiddunur, India) after applications at the standard and double doses of 75 + 150 and of 150 + 300 g ha(-1) of the formulated product, trifloxystrobin (25%) + tebuconazole (50%) (Nativo 75 WG). The fungicides were determined by gas chromatography (GC) and confirmed by gas chromatography-mass spectrometry (GC-MS). Extraction and purification of the samples were carried out by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method after validating the analytical parameters. Initial residues of trifloxystrobin on gherkin fruits were 0.335 and 0.65 mg kg(-1) at Bangalore, and 0.34 and 0.615 mg kg(-1) at Gouribiddunur. Tebuconazole residues were 0.842 and 1.682 mg kg(-1) at Bangalore, and 0.71 and 1.34 mg kg(-1) at Gouribiddunur. Residue dissipation of the fungicides followed first-order rate kinetics. Trifloxystrobin residues dissipated at the half-life of 2.9-3.7 days, and tebuconazole at 3.2 days. At the standard dose treatment, trifloxystrobin residues dissipated to below the maximum residue limit (MRL) of 0.2 mg kg(-1) (European Union) within 3 days at both the locations. Residues of the metabolite CGA 321113 was less than the limit of quantification (LOQ; 0.05 mg kg(-1)) on all sampling days. Tebuconazole residues dissipated to below its MRL (0.05 mg kg(-1)) within 14 and 11 days, at Bangalore and Gouribiddunur, respectively. From the two trials, it was concluded that the required pre-harvest interval (PHI) for the combination formulation was 14 days. Application of Nativo 75 WG should be given before flowering to allow the residues to dissipate below the MRLs at harvest.

Topics: Acetates; Cucumis sativus; Environmental Monitoring; Fruit; Fungicides, Industrial; Gas Chromatography-Mass Spectrometry; Half-Life; Imines; India; Kinetics; Limit of Detection; Methacrylates; Pesticide Residues; Soil Pollutants; Strobilurins; Triazoles; Vegetables

This paper reports the in vitro and in vivo bioefficacy of a combination fungicide trifloxystrobin (25%) + tebuconazole (50%) against early blight disease of tomato (Lycopersicon esculentum Mill.) caused by Alternaria solani and their corresponding pre-harvest intervals (PHI) with reference to the maximum residue limits (European Union). Bioefficacy of the test fungicide combination revealed that in vitro conditions manifested the best control (75.1%) at 350 mg kg(-1) against 76.2% control under field conditions. A sample preparation method based on ethyl acetate extraction and estimation by LC-MS multiple reaction monitoring (MRM) was validated in tomato fruits at 0.01 mg/kg and dissipation studies were conducted in field at single and double doses. The residues of both the compounds on all the sampling days were below the European Union maximum residue limits (EU-MRLs) and the maximum permissible intakes (MPIs) were calculated on the basis of prescribed acceptable daily intake (ADI). The combined bioefficacy and residue dynamics information will support label-claim of this fungicide combination for the management of early blight in tomato.

Topics: Acetates; Alternaria; Chromatography, Liquid; Dose-Response Relationship, Drug; European Union; Fungicides, Industrial; Imines; Mass Spectrometry; Methacrylates; Pesticide Residues; Plant Diseases; Solanum lycopersicum; Strobilurins; Triazoles

The persistence and dissipation kinetics of trifloxystrobin and tebuconazole on onion were studied after application of their combination formulation at a standard and double dose of 75 + 150 and 150 + 300 g a.i. ha(-1). The fungicides were extracted with acetone, cleaned-up using activated charcoal (trifloxystrobin) and neutral alumina (tebuconazole). Analysis was carried out by gas chromatograph (GC) and confirmed by gas chromatograph mass spectrometry (GC-MS). The recovery was above 80% and limit of quantification (LOQ) 0.05 mg kg(-1) for both fungicides. Initial residue deposits of trifloxystrobin were 0.68 and 1.01 mg kg(-1) and tebuconazole 0.673 and 1.95 mg kg(-1) from standard and double dose treatments, respectively. Dissipation of the fungicides followed first-order kinetics and the half life of degradation was 6-6.6 days. Matured onion bulb (and field soil) harvested after 30 days was free from fungicide residues. These findings suggest recommended safe pre-harvest interval (PHI) of 14 and 25 days for spring onion consumption after treatment of Nativo 75 WG at the standard and double doses, respectively. Matured onion bulbs at harvest were free from fungicide residues.

Topics: Acetates; Environmental Monitoring; Fungicides, Industrial; Gas Chromatography-Mass Spectrometry; Imines; India; Methacrylates; Onions; Soil Pollutants; Strobilurins; Triazoles

A new combinational fungicide formulation trifloxystrobin 25%+tebuconazole 50% (Nativo 75WG), introduced as a part of resistance management strategy, was studied for dissipation behaviour on apple fruits. Nativo 75WG was sprayed twice at the rate of 400 g and 800 g a.i. ha(-1) equal to trifloxystrobin application rate of 100 and 200 g a.i. ha(-1) and tebuconazole at application rate of 200 and 400 g a.i. ha(-1) at four different locations in the Northwest Himalayan region of India. The fruit samples collected at 10d interval and soil samples taken at harvest time were analyzed after second spray. The residual concentrations of trifloxystrobin, its acid metabolite CGA 321113 and tebuconazole were measured. Residues of both fungicides were determined by using gas chromatograph, Agilent 6890N having electron capture detector. The mean initial deposits of trifloxystrobin at four locations were found to be in the range of 0.333-0.387 mg kg(-1) and 0.512-0.714 mg kg(-1) at the application rate of 100 and 200 g a.i. ha(-1), and half-life were found between 19.38-24.93 d and 19.84-28.86 d at the respective doses. The Σ-trifloxystrobin and tebuconazole residues were below determination limit in 40 d apple fruits and soil samples. Initial deposits of trifloxystrobin and tebuconazole were below their Codex MRLs at the respective single doses. The half life value of the tebuconazole deposits ranged between 19.38-25.99 d and 19.84-28.86 d at the respective single and double dose. The study thus suggests 1d pre harvest interval for safe consumption of apple fruit after the application of Nativo 75 WG at single dose.

Topics: Acetates; Chromatography, Gas; Environmental Monitoring; Fruit; Fungicides, Industrial; Half-Life; Imines; India; Kinetics; Malus; Methacrylates; Pesticide Residues; Soil Pollutants; Strobilurins; Triazoles

Dissipation of trifloxystrobin and tebuconazole were studied following two applications of a combination formulation of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) @ 250 and 500 g ha(-1) at 10 days interval. Samples of chili were collected at 0, 1, 3, 5, 7, 10 and 15 days after the last application. Red chili and soil samples were collected after 20 days of last application. Half-life period for trifloxystrobin were found to be 1.81 and 1.58 days and for tebuconazole these values were observed to be 1.37 and 1.41 days, respectively, at single and double the application rates. Trifloxystrobin residues dissipated below its limit of quantification (LOQ) of 0.01 mg kg(-1) after 5 and 7 days, respectively, at single and double the application dosages whereas tebuconazole residues took 7 and 10 days, respectively. Red chili & soil samples collected after 20 days did not reveal the presence of trifloxystrobin and tebuconazole at their determination limit of 0.01 mg kg(-1).

Topics: Acetates; Capsicum; Fungicides, Industrial; Half-Life; Imines; Kinetics; Methacrylates; Models, Chemical; Soil; Soil Pollutants; Strobilurins; Triazoles

Following single application of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) on wheat crop @ 300 and 600 g ha(-1), resulting in active application of trifloxystrobin @ 75.0 and 150.0 g a.i. ha(-1) and tebuconazole @ 150 and 300 g a.i. ha(-1), the average initial deposits of trifloxystrobin on wheat leaves were 5.54 and 8.30 mg kg(-1), and that of tebuconazole were 14.66 and 27.94 mg kg(-1), respectively. Half-life values for trifloxystrobin were observed to be 2.80 and 2.51 days whereas those for tebuconazole were found to be 2.46 and 1.85 days at recommended and double the recommended dosages, respectively. The residues of trifloxystrobin and tebuconazole dissipated to the extent of >89% at both the dosages after 7 days. Wheat grain samples at harvest having pre harvest interval of 140 days did not show the presence of trifloxystrobin and tebuconazole at their determination limit of 0.01 mg kg(-1).

Topics: Acetates; Fungicides, Industrial; Half-Life; Imines; Kinetics; Methacrylates; Plant Leaves; Soil Pollutants; Strobilurins; Triazoles; Triticum

A new analytical method using QuEChERS procedure by gas chromatography with a nitrogen-phosphorus detector (GC-NPD) and ion trap mass spectrometry (GC-IT-MS) for the quantitative determination of tebuconazole, trifloxystrobin and its metabolite trifloxystrobin acid has been developed and validated. The analytes were extracted from five fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to GC analysis. The present methods provided sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ) of 0.4-7 and 1.2-20 µg/kg for GC-IT-MS/MS and GC-NPD. The recoveries were, on average, 68-117 and 68-121%, respectively, for three compounds by GC-NPD and GC-IT-MS/MS with intra-day precision achieved with an RSD of 2.7-19.1%. The inter-day precision was better than 15.1% as determined by GC-NPD. The QuEChERS procedure, by using two sorbents (PSA and C18) and the matrix-matched standards, gave satisfactory recoveries and RSD values in different matrices. IT-MS acquisition provided higher specificity and selectivity for pesticides and better limit of detection and quantification. However, the repeatability and precision of NPD method were better compared with IT-MS.

Topics: Acetates; Brassica; Fruit; Gas Chromatography-Mass Spectrometry; Imines; Methacrylates; Pesticide Residues; Reproducibility of Results; Sensitivity and Specificity; Strobilurins; Tandem Mass Spectrometry; Triazoles; Vegetables; Vitis

Following four foliar applications of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) on grapes @ 175 and 350 g/ha, resulting in active applications of trifloxystrobin @ 43.75 and 87.5 g a.i./ha and that of tebuconazole @ 87.5 and 175 g a.i./ha, the average initial deposits of trifloxystrobin were observed to be 7.76 and 15.53 mg/kg, respectively, at single and double the application rates. These residue levels dissipated to >85% after 10 days of its application at both the dosages. Similarly, the average initial deposits of tebuconazole were observed to be 13.84 and 26.55 mg/kg at single and double the application rate, respectively. These residue levels dissipated to >90% after 10 days of application at both the dosages. The half-life (t(1/2)) periods of trifloxystrobin on grape leaves were observed to be 2.92 and 3.48 days at single and double application rates, respectively, whereas these values were 2.68 and 3.96 days for tebuconazole. Ripe grape berries and soil samples collected at harvest which happened to be 34 days after the last application, did not show the presence of residues of trifloxystrobin and tebuconazole at their determination limit of 0.01 and 0.02 mg/kg, respectively.

Topics: Acetates; Fungicides, Industrial; Half-Life; Imines; Methacrylates; Plant Leaves; Soil Pollutants; Strobilurins; Triazoles; Vitis

A mixture of trifloxystrobin and tebuconazole is excellent in controlling both powdery and downy mildew of grapes. The objective of the present work was to study the behaviour of trifloxystrobin and tebuconazole on grape berries and soil following treatment with Nativo 75 WG, a formulation containing both fungicides (trifloxystrobin 250 + tebuconazole 500 g kg(-1)). This study was carried out for planned registration of this mixture for use on grapes in India.. Initial residue deposits of trifloxystrobin and tebuconazole on grapes were below their maximum residue limit (MRL) of 0.5 and 2 mg kg(-1), respectively, when Nativo 75 WG was applied at the recommended dose of 175 g product ha(-1). The residues dissipated gradually to 0.02 and 0.05 mg kg(-1) by 30 days, and were below the quantifiable limit of 0.01 mg kg(-1) at the time of harvest (60 days after the last treatment). Trifloxystrobin and tebuconazole dissipated at a pre-harvest interval (PHI) of 36 and 34 days, respectively, from the recommended treatment dose. The acid metabolite of trifloxystrobin, CGA 321 113, was not detected in grape berries at any point in time. Soil at harvest was free of any pesticide residues.. Residue levels of both trifloxystrobin and tebuconazole were below MRLs when grapes were harvested 30 days after the last of four applications of 175 g product ha(-1) (trifloxystrobin 44 g AI ha(-1), tebuconazole 88 g AI ha(-1)) under the semi-arid tropical climatic conditions of India.

Topics: Acetates; Chemistry, Pharmaceutical; Chromatography, Gas; Dose-Response Relationship, Drug; Droughts; Fruit; Fungicides, Industrial; Imines; Methacrylates; Plant Diseases; Soil; Strobilurins; Triazoles; Tropical Climate; Vitis

In Côte-d'Ivoire, banana leaf surfaces are attacked by Mycosphaerella fijiensis var. difformis, Cladosporium musae, and Deigthonielle torulosa. Control is based on fungicides recommanded for Mycosphaerella fijiensis. Fungicides belonging to triazoles and strobilurines types were added, at different concentrations, to the PDA medium, using this PDA medium containing no fungicide as the control. Mycelium disc and spores of Cladosporium musae, Mycosphaerella fijiensis and Deightoniella torulosa were put on the different media. Total inhibition of mycelium growth of every fungus on the PDA amended with propiconazole was observed. The fungicides used show different activities according to their concentration and their mode of action. The application of a fungicide should talke into account the pathogenic fungus involved in the leaf attacked. Against Mycosphaerella fijiensis var. difformis, the Ci(50) are different according to the concentrations (0.44 to 1.06 ppm). Correlations ranked from 0.71 to 0.91 are also different according to fungicide used. The Ci(50) of Cladosporium musae (0.10 to 2.44 ppm) and Deightoniella torulosa (0.26 to 0.52 ppm) are different and their correlations are respectively 0.78 to 0.99 and 0.86 to 0.95. An assessment of the sensitivity of parasitic fungi of banana can be made by mycelium growth measurement of fungi isolated from resistance zones.

Topics: Acetates; Ascomycota; Cladosporium; Cote d'Ivoire; Drug Resistance, Fungal; Drug Resistance, Multiple, Fungal; Fungicides, Industrial; Imines; In Vitro Techniques; Methacrylates; Musa; Mycelium; Plant Leaves; Species Specificity; Spiro Compounds; Strobilurins; Triazoles

Strobilurin fungicides have a broad spectrum activity against all major foliar pathogens of wheat. In addition to this extraordinary fungicidal activity side-effects have been reported which result in higher yields of cereals, e.g. the reduction of respiration, delayed leaf senescence, activation of nitrogen metabolism as well as increased tolerance against abiotic stress factors. In the vegetation period 2000/2001 field trials were carried out at three sites in North Rhine-Westphalia to study the effects of three strobilurin fungicides on the yield formation of six winter wheat varieties. The strobilurins were applied two times as the commercial products Stratego (trifloxystrobin + propiconazole), Amistar/Pronto Plus (azoxystrobin/spiroxamine + tebuconazole) and Juwel Top (kresoxim-methyl + epoxiconazole + fenpropimorph. Fungicide-treated plants were kept disease-free by an initial azole-application in GS 31 in order to exclude disease effects on physiological parameters relevant to yield formation. Photosynthetic electron transport of strobilurin-treated wheat, was improved as early as at GS 65 compared to azole-treated plants. Differences often increased with growth stage and were closely related to a delay in leaf senescence. A higher photosynthetic activity of strobilurin-treated plants was confirmed by gas exchange and chlorophyll fluorescence measurements under field conditions. The yield benefit of wheat from strobilurin treatments varied from 2% to 9% depending on an improved photosynthetic capacity due to a higher and/or prolonged activity. Neither yield potential nor disease susceptibility of the cultivar had an effect on the height of the extra yield which, in contrast was modified by location and wheat genotype.

Topics: Acetates; Acrylates; Azoles; Chlorophyll; Epoxy Compounds; Fungicides, Industrial; Germany; Imines; Methacrylates; Morpholines; Phenylacetates; Photosynthesis; Pyrimidines; Strobilurins; Triazoles; Triticum